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http://cicy.repositorioinstitucional.mx/jspui/handle/1003/165| Molecular phylogenetics ofAlternanthera (Gomphrenoideae, Amaranthaceae): resolving a complex taxonomic history caused by different interpretations of morphological characters in a lineage with C4 and C3–C4 intermediate species | |
| IVONNE SANCHEZ DEL PINO | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| Alternanthera(Amaranthaceae) is a diverse genus (80–200 species) largely restricted to the American Tropics. With PederseniaandTidestromia, it makes up the ‘alternantheroid’ clade in Gomphrenoideae. Parsimony and Bayesian analyses of nucleotide sequences of nuclear (ITS) and plastid (rpl16, trnL-F) and morphological characters identify that the capitate stigma ofAlternantherais a synapomorpy within the alternantheroids. WithinAlternanthera, two major clades were resolved, both of which were marked by homoplasious characters of the gynoecium: Clade A [99% jackknife (JK); 1.0 posterior probability (PP)] with nine species and Clade B (60% JK; 0.98 PP) with 22 species. Four subclades (B1–B4), strongly supported statistically, were identified in Clade B. Previous subgeneric classifications ofAlternantheraappear artificial in light of our new molecular phylogenetic analyses. Most major lineages are congruently resolved by nuclear and plastid data but some incongruence between the nrITS and plastid phylogenetic trees suggests hybridization may have played a role in the rampant speciation inAlternanthera. Whereas C4photosynthesis appears to have evolved in a single clade, the position ofA. littoralisvar.maritima(C3) in this clade may be explained by hybrid speciation or limited sampling rather than a reversal from C4 to C3. All C3–C4 intermediates belong to a different clade that also contains C3 species, but species limits, including the widely studiedA. tenella, are unclear. The clade including A. tenellaandA. halimifoliaalso contains most of the species endemic to the Galápagos whereasA. nesiotes, also endemic to the islands, is nested among widespread American taxa. This suggests that the Galápagos radiation ofAlternantheramay have arisen from at least two independent colonization events followed by a subsequent radiation in the former lineage. | |
| 01-04-2012 | |
| Artículo | |
| CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA | |
| Aparece en las colecciones: | Artículos de Investigación Arbitrados |
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